Tailstock with multiple drive modes



y 27, 1955 P. F. DE VALLIERE 3,

TAILSTOCK WITH MULTIPLE DRIVE'MODES Filed June 19. 1961 INVENTOR PIERRE FRANCO/S DE VALL/ERE United States Patent 3,196,719 TAILSTOCK WITH MULTIPLE DRIVE MODES Pierre Francois rle Valliere, 14 Avenue de Bretteville, Neuilly-sur-Seine (Seine), France Filed June 19, 1961, Ser. No. 117,875 Claims priority, application France, June 24, 1960, 831,015, Patent 1,269,144 6 Claims. (Cl. 82-31) The present invention relates to a tailstock adopted for permitting multiple drive modes, namely drive modes offering either manual operation at slow or high speed, or mechanical operation, the driving means being designed so that changeovers from one mode to another take place in response to movement of a single member.

In the case of a tailstock capable of slow speed operation by means of an adjustment handwheel, as an example, and high speed operation in response to rotation of a starwheel, the single control member may consist of a nut which is integral with said handwheel and operated by an eccentric bush which moves the tapped part of said nut into or out of engagement with a rack rigidly connected to the cylinder of said tailstock, said rack being cut in the form of a screw-thread and being in constant mesh with a matching transverse pinion to which may be connected the star-wheel.

In the case of a tailstock providing three dilierent drive modes, to wit a slow speed by means of a handwheel, at high speed by means of a star-wheel, and in feed motion in response to some appropriate mechanism, the single control member consists of a shifting pinion which can be selectively placed in an inoperative position, in mesh with a screw rigidly connected to the handwheel, or in mesh with a mechanically-driven worm gear, said shifting pinion cooperating with a broad pinion which is in constant mesh with said tailstock cylinder rack. Assemblies obtained in this way are convenient to use, highly accurate and quite inexpensive to produce.

The description which follows by way of example and not of limitation, will give a clear understanding of how the invention may be performed when taken in conjunction with the attached drawing, wherein:

FIG. 1 is an axial section of a tailstock with three control modes, said section being taken along the broken line I-I in FIG. 2; FIG. 2 is a cross-section taken along the line II-II in FIG. 1; and

FIG. 3 is a section taken along the line III-III in FIG. 1.

The mechanism illustrated in the drawing comprises a tailstock cylinder 16 which is provided with a rack 17 rigidly secured thereto. This rack cooperates with a broad transverse pinion 18 which projects to one side of said sleeve. The rear of cylinder 16 is inserted into a bush 19 which is mounted concentrically on said cylinder and rotatably supported by at least one ball-bearing 20 housed in the tailstock body 21. An operating handwheel 22 is keyed to the sleeve 19, onto the other end of which are cut external teeth 23.

A shaft 24 provided with at least one spline 25 is disposed parallel to the axis of the broad pinion 18 and has slidably mounted thereon, a shifting pinion 26. An operating pin 27, having a protruding driving-head 28, is fitted into the head of the tailstock and carries either integrally or keyed thereon a threaded portion 29 which is so disposed as to enable the shifting pinion 26 to occupy ice,

one of three positions: firstly, a position wherein it meshes simultaneously with the threaded portion 29 and the pinion 18; secondly, a position in which it stays in mesh with the pinion 18 only; and, thirdly, a position wherein it meshes simultaneously with the teeth 23 and the pinion 18. To this end, the shifting pinion may be actuated by any convenient means, for instance by means of a fork (not shown).

In the first position, the shifting pinion couples the pin 27 to the pinion 18 to permit mechanical driving of the cylinder 16. It is to be noted that the disposition of the pin 27, shown in the figures as being parallel to the axis of the sleeve 16, may have any other configuration susceptible of facilitating its junction with a mechanical driving member.

In the inoperative position of the shifting pinion 26, the cylinder 16 can be axially translated manually at high speed by means, say, of a star-wheel mounted on the supporting shaft of pinion 18 or on the shaft 24 of shifting pinion 26. I

In the third position, the shifting pinion 26 allows the handwheel 22 to be coupled with the cylinder 16, whereby slow manual irreversible feed can be imparted to the latter.

The teeth 23 preferably consist of sections of spiral threading, and this also applies to the teeth of threaded portion 29. Thus, the inclination of the teeth may be identical for both pinions. The teeth 23 may be of the single thread type, while those of threaded portion 29 may comprise two threads, the ratio between the diameters being two to one.

What I claim is:

1. A tailstock device comprising a slidably supported cylinder, a rack coupled to the cylinder for movement therewith, a pinion gear adapted for being externally driven and in constant mesh with said rack, a handwheel coaxially disposed with respect to said cylinder and traversed by said cylinder and means for selectively connecting said handwheel to said rack in irreversible driving relation whereby said cylinder can be selectively driven externally and sensitively through said pinion gear and irreversibly by said handwheel also through said pinion gear.

2. A tailstock device comprising a slidably supported cylinder, a rack coupled to the cylinder for movement therewith, a pinion gear adapted for being externally driven and in mesh with said rack, a handwheel, said pinion gear having an axis of rotation extending transverse of said cylinder, a shifting pinion gear parallel to the first said gear and movable along an axis parallel thereto between three positions, said shifting gear in a first position engaging the first said pinion gear for coupling the same to a mechanical drive, said shitting gear in a second position being in a free-wheeling position to permit the first said pinion gear to drive the rack, said handwheel being drivingly connected through said shifting gear to the first said pinion gear in the third position of the shifting gear whereby the cylinder can be driven by the handwheel.

3. A tailstock as claimed in claim 2 comprising a bush connected to said handwheel for rotation therewith, said bush having an internally threaded surface which is in driving engagement with said shifting gear with the latter in said third position thereof.

4. A tailstock as claimed in claim 3 wherein said bush is concentrically mounted with respect to said cylinder.

5, A tailstock' as claimed in claim 2 comprising a thisaded Pin which is adapted tor onnection to a mechanical drive, said pin being in threaded engagement with the shifting gear with the latter in said first position.

6. A tailstock as claimed in claim 5, comprising a bush connected to said handwheel for rotation therewith, said bush having an internally threaded surface which is in driving engagement with said shifting gear with the latter in said third position thereof, and wherein said pin and 4 References Cited by the Examiner UNITED STATES PATENTS 1,811,504 6/31 John son'et a1. 82-31 2,115,094 4/38 Bucklein 8231 2,391,154 12/45 Groene 8231 2,865,242 12/58 Kemper et al. 823l ANDREW R. JUHASZ, Primary Examiner.

bush include threads in a number proportional to the 10 RICHARD H. EANES, JR.,-WI'L'LIAM W. DYER, In,

d ame r o @129 rar st e n nd bu Examiners. 

1. A TAILSTOCK DEVICE COMPRISING A SLIDABLY SUPPORTED CYLINDER, A RACK COUPLED TO THE CYLINDER FOR MOVEMENT THEREWITH, A PINION GEAR ADAPTED FOR BEING EXTERNALLY DRIVEN AND IN CONSTANT MESH WITH SAID RACK, A HANDWHEEL COAXIALLY DISPOSED WITH RESPECT TO SAID CYLINDER AND TRAVERSED BY SAID CYLINDER AND MEANS FOR SELECTIVELY CONNECTING SAID HANDWHEEL TO SAID RACK IN IRREVISIBLE DRIV- 